In image composition, a new image can be blended from a background image and a foreground image through use of an alpha matte of the image. On the other hand, separation of the alpha matte, the foreground and the background from a given image is a more difficult process, often referred to as the pulling of matte problem, or simply matting.
For example, in blue screen matting, the alpha matte and foreground can be readily reconstructed because the background is known (e.g., from a user-controlled environment). In contrast, for natural image matting, the alpha matte, the foreground and the background need to be estimated. Further, natural image matting is inherently under-constrained due to the number of unknowns of the matting equation. Thus, a need exists for improved natural image matting techniques. Various exemplary techniques described herein aim to address this and other issues associated with matting.